Methods for beam determination after beam pair link indication

Abstract

Methods, systems, and devices for wireless communications are described that provide for signaling and switching of beam pair links (BPLs) for directional transmission beams between a base station and a user equipment (UE). A threshold value may be determined, which corresponds to an amount of time for a UE to receive and decode control information, and apply a different BPL than a current BPL that that is in use. The UE may maintain a BPL for data, which is used during data transmission time intervals (TTIs) until an indication is received to change the BPL for data. The UE and the base station may determine to change between BPLs based at least in part on the threshold value and a scheduling offset between a control channel transmission that allocates resources for a data TTI and a start of the data TTI.

What is claimed is: 
     
       1. A method for wireless communication, comprising:
 establishing, at a user equipment (UE), a first beam pair link (BPL); 
 identifying a threshold value corresponding to an amount of time needed by the UE to decode an indication of a BPL switch and apply a different BPL than the first BPL based at least in part on the indication; 
 receiving a first control information transmission at a first time, the first control information transmission including a scheduling offset, an assignment for a first data transmission time interval (TTI) that starts at a second time corresponding to the first time plus the scheduling offset, and a BPL indication; 
 determining, based at least in part on the threshold value and the scheduling offset, whether to switch a BPL for data associated with the first BPL and a switching time for making the switch; and 
 switching the BPL for data to a second BPL at the switching time responsive to determining to switch the BPL for data. 
 
     
     
       2. The method of  claim 1 , wherein the second BPL is indicated in the BPL indication. 
     
     
       3. The method of  claim 1 , wherein the determining comprises:
 determining to switch the BPL for data based at least in part on determining that the scheduling offset is greater than or equal to the threshold value, and to switch the BPL for data to the second BPL at the second time. 
 
     
     
       4. The method of  claim 1 , wherein the determining comprises:
 determining to maintain the first BPL as the BPL for data based on determining that the scheduling offset is less than the threshold value. 
 
     
     
       5. The method of  claim 4 , further comprising:
 identifying that an error in receiving a prior BPL indication has occurred based at least in part on determining that the scheduling offset is less than the threshold value, and the BPL indicated differs from the BPL for data at the second time. 
 
     
     
       6. The method of  claim 5 , further comprising:
 correcting, after the identifying the error in receiving the prior BPL indication, the BPL for data as maintained by the UE and using the corrected BPL for data after the first time plus the threshold value if it is not overwritten by any other signaled switch of the BPL for data occurring between the second time and the first time plus threshold value. 
 
     
     
       7. The method of  claim 1 , wherein the determining comprises:
 determining to switch the BPL for data to the second BPL, based at least in part on determining that the scheduling offset is less than the threshold value, effective starting at the first time plus the threshold value. 
 
     
     
       8. The method of  claim 1 , wherein the determining comprises:
 determining to switch the BPL for data to the second BPL at the first time plus the threshold value irrespective of the scheduling offset. 
 
     
     
       9. The method of  claim 1 , further comprising:
 maintaining the BPL for data, which is initialized with the first BPL and is used during the data TTIs, wherein the data TTIs include uplink data TTIs, downlink data TTIs, or combinations thereof. 
 
     
     
       10. A method for wireless communication, comprising:
 establishing, at a base station, a first beam pair link (BPL); 
 changing a BPL for data associated with the first BPL to a second BPL based at least on one or more channel conditions; 
 identifying a threshold value corresponding to an amount of time for the UE to decode an indication of a BPL switch and apply a different BPL based at least in part on the indication; 
 allocating resources for the UE for a first data transmission time interval (TTI); 
 determining a scheduling offset between a control information transmission indicating the allocated resources and a start of the first data TTI; and 
 transmitting control information to the UE, the control information including the scheduling offset, an assignment for the first data TTI, and a BPL indication, and wherein the scheduling offset, a time of the control information transmission, the threshold value, and the BPL indication indicate to the UE whether the BPL for data will change and a BPL change time. 
 
     
     
       11. The method of  claim 10 , wherein a change of the BPL for data for the first data TTI is indicated by the scheduling offset being greater than or equal to the threshold value. 
     
     
       12. The method of  claim 10 , further comprising:
 determining not to convey a change of the BPL for data when the scheduling offset is less than the threshold value. 
 
     
     
       13. The method of  claim 12 , further comprising:
 determining, when the scheduling offset is less than the threshold value, the BPL indicated in the control information indicates the BPL used for the first data TTI. 
 
     
     
       14. The method of  claim 10 , wherein a change of the BPL for data is indicated by the scheduling offset being less than the threshold value, and the BPL change time corresponds to the time of the control information transmission plus the threshold value. 
     
     
       15. The method of  claim 10 , wherein a change of the BPL for data is indicated irrespective of the scheduling offset, and the BPL change time corresponds to the time of the control information transmission plus the threshold value. 
     
     
       16. The method of  claim 10 , further comprising:
 maintaining the BPL for data, which is initialized with the first BPL and is used during data TTIs, wherein the data TTIs include uplink data TTIs, downlink data TTIs, or combinations thereof. 
 
     
     
       17. An apparatus for wireless communication, comprising:
 means for establishing, at a user equipment, a first beam pair link (BPL); 
 means for identifying a threshold value corresponding to an amount of time needed by the UE to decode an indication of a BPL switch and apply a different BPL than the first BPL based at least in part on the indication; 
 means for receiving a first control information transmission at a first time, the first control information transmission including a scheduling offset, an assignment for a first data transmission time interval (TTI) that starts at a second time corresponding to the first time plus the scheduling offset, and a BPL indication; 
 means for determining, based at least in part on the threshold value and the scheduling offset, whether to switch a BPL for data associated with the first BPL and a switching time for making the switch; and 
 means for switching the BPL for data to a second BPL at the switching time responsive to determining to switch the BPL for data. 
 
     
     
       18. The apparatus of  claim 17 , wherein the means for determining determines to switch the BPL for data based at least in part on determining that the scheduling offset is greater than or equal to the threshold value, and to switch the BPL for data to the second BPL at the second time. 
     
     
       19. The apparatus of  claim 17 , wherein the means for determining determines to maintain the first BPL as the BPL for data based on determining that the scheduling offset is less than the threshold value. 
     
     
       20. The apparatus of  claim 19 , further comprising:
 means for identifying that an error in receiving a prior BPL indication has occurred based at least in part on determining that the scheduling offset is less than the threshold value, and the BPL indicated in the first control information transmission indicates the BPL used by the base station for the first data TTI differs from the first BPL. 
 
     
     
       21. The apparatus of  claim 17 , wherein the means for determining determines to switch the BPL for data to the second BPL, based at least in part on determining that the scheduling offset is less than the threshold value, effective starting at the first time plus the threshold value. 
     
     
       22. The apparatus of  claim 17 , wherein the means for determining determines to switch the BPL for data to the second BPL at the first time plus the threshold value irrespective of the scheduling offset. 
     
     
       23. An apparatus for wireless communication, comprising:
 means for establishing, at a base station, a first beam pair link (BPL); 
 means for changing a BPL for data associated with the first BPL to a second BPL based at least on one or more channel conditions; 
 means for identifying a threshold value corresponding to an amount of time for the UE to decode an indication of a BPL switch and apply a different BPL based at least in part on the indication; 
 means for allocating resources for the UE for a first data transmission time interval (TTI); 
 means for determining a scheduling offset between a control information transmission indicating the allocated resources and a start of the first data TTI; and 
 means for transmitting control information to the UE, the control information including the scheduling offset, an assignment for the first data TTI, and a BPL indication, and wherein the scheduling offset, a time of the control information transmission, the threshold value, and the BPL indication indicate to the UE whether the BPL for data will change and a BPL change time. 
 
     
     
       24. The apparatus of  claim 23 , wherein a change of the BPL for data for the first data TTI is indicated by the scheduling offset being greater than or equal to the threshold value. 
     
     
       25. The apparatus of  claim 23 , wherein the means for changing determines not to convey a change of the BPL for data when the scheduling offset is less than the threshold value. 
     
     
       26. The apparatus of  claim 25 , wherein the means for changing determines, when the scheduling offset is less than the threshold value, the BPL indicated in the control information is to indicate the BPL used for the first data TTI. 
     
     
       27. The apparatus of  claim 23 , wherein a change of the BPL for data is indicated by the scheduling offset being less than the threshold value, and the BPL change time corresponds to the time of the control information transmission plus the threshold value. 
     
     
       28. The apparatus of  claim 23 , wherein a change of the BPL for data is indicated irrespective of the scheduling offset, and the BPL change time corresponds to the time of the control information transmission plus the threshold value. 
     
     
       29. An apparatus for wireless communication, comprising:
 a processor; 
 memory in electronic communication with the processor; and 
 instructions stored in the memory and executable by the processor to cause the apparatus to:
 establish, at a user equipment, a first beam pair link (BPL); 
 identify a threshold value corresponding to an amount of time needed by the UE to decode an indication of a BPL switch and apply a different BPL than the first BPL based at least in part on the indication; 
 receive a first control information transmission at a first time, the first control information transmission including a scheduling offset, an assignment for a first data transmission time interval (TTI) that starts at a second time corresponding to the first time plus the scheduling offset, and a BPL indication; 
 determine, based at least in part on the threshold value and the scheduling offset, whether to switch a BPL for data associated with the first BPL and a switching time for making the switch; and 
 switch the BPL for data to a second BPL at the switching time responsive to determining to switch the BPL for data. 
 
 
     
     
       30. The apparatus of  claim 29 , further comprising:
 a receiver coupled with the processor and memory that receives the first control information transmission and one or more downlink data TTI transmissions; and 
 a transmitter coupled with the processor and memory that transmits one or more uplink data TTI transmissions. 
 
     
     
       31. An apparatus for wireless communication, comprising:
 a processor; 
 memory in electronic communication with the processor; and 
 instructions stored in the memory and executable by the processor to cause the apparatus to:
 establish, at a base station, a first beam pair link (BPL); 
 change a BPL for data associated with the first BPL to a second BPL based at least on one or more channel conditions; 
 identify a threshold value corresponding to an amount of time for the UE to decode an indication of a BPL switch and apply a different BPL based at least in part on the indication; 
 allocate resources for the UE for a first data transmission time interval (TTI); 
 determine a scheduling offset between a control information transmission indicating the allocated resources and a start of the first data TTI; and 
 transmit control information to the UE, the control information including the scheduling offset, an assignment for the first data TTI, and a BPL indication, and wherein the scheduling offset, a time of the control information transmission, the threshold value, and the BPL indication indicate to the UE whether the BPL for data will change and a BPL change time. 
 
 
     
     
       32. The apparatus of  claim 31 , further comprising:
 a transmitter coupled with the processor and memory that transmits the control information and one or more downlink data TTI transmissions to the UE; and 
 a receiver coupled with the processor and memory that receives one or more uplink data TTI transmissions. 
 
     
     
       33. A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:
 establish, at a user equipment, a first beam pair link (BPL); 
 identify a threshold value corresponding to an amount of time needed by the UE to decode an indication of a BPL switch and apply a different BPL than the first BPL based at least in part on the indication; 
 receive a first control information transmission at a first time, the first control information transmission including a scheduling offset, an assignment for a first data transmission time interval (TTI) that starts at a second time corresponding to the first time plus the scheduling offset, and a BPL indication; 
 determine, based at least in part on the threshold value and the scheduling offset, whether to switch a BPL for data associated with the first BPL and a switching time for making the switch; and 
 switch the BPL for data to a second BPL at the switching time responsive to determining to switch the BPL for data. 
 
     
     
       34. A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:
 establish, at a base station, a first beam pair link (BPL); 
 change a BPL for data associated with the first BPL to a second BPL based at least on one or more channel conditions; 
 identify a threshold value corresponding to an amount of time for the UE to decode an indication of a BPL switch and apply a different BPL based at least in part on the indication; 
 allocate resources for the UE for a first data transmission time interval (TTI); 
 determine a scheduling offset between a control information transmission indicating the allocated resources and a start of the first data TTI; and 
 transmit control information to the UE, the control information including the scheduling offset, an assignment for the first data TTI, and a BPL indication, and wherein the scheduling offset, a time of the control information transmission, the threshold value, and the BPL indication indicate to the UE whether the BPL for data will change and a BPL change time.